Patent GB-494116-A (GB)
Title: Improvements in coin-freed prepayment mechanism
IPC: G07F15/06
Filed: 1937-05-05
Abstract: 494,116. Prepayment mechanism for meters. ASH, F. S., JACKSON, F., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. May 5, 1937, No. 12888. [Class 27] In a prepayment meter the supply of commodity is controlled by a member 24, Fig. 2, co-operating with a cam 23 having an interrupted surface 26 and an uninterrupted surface 25. After a portion of a revolution of the cam 23 in the direction corresponding to prepayment away from its zero position, where the supply is cut off by the trip lever 24 leaving the surface 26, the cam is moved axially so that the trip lever 24 engages the surface 25 and the cam is capable of rotating through a number of revolutions, thereby allowing a large amount of prepayment. The cam 23 is rotated in the reverse direction by the meter and during its last revolution to zero position it is moved back axially for the lever 24 to engage the surface 26. If a basic charge mechanism is provided, the cam 23 is rotated further in the reverse direction to register arrears of fixed charges and it is also moved further axially out of co-operation with the lever 24 so that it can make several revolutions in the reverse direction to accumulate a large amount of arrears. As shown applied to a two-part tariff meter, the cam 23 on the shaft 22 is rotated in reverse directions from the planet carrier 17 of the quantity differential 8 through gearing 19, 20, 21, the planet carrier 17 being rotated in one direction by prepayment and in the other by the consumption meter and basic charge motor. The cam is moved axially by a pin 37 on a lever 38 engaging a grooved collar 36 fixed to the shaft 22. The lever 38 is carried by a vertical rod 39 having an arm 40 provided with a roller 41 engaging a control cam 42. This cam comprises two dwells 44, 45 joined by a sloping portion 46. The roller 41 is kept against the cam 42 by a spring 43 acting on the lever 38. When the roller 41 is in contact with the dwell 45, the surface 25 of the cam 23 is in contact with the trip lever 24 and, when it is in contact with the dwell 44, the cam 23 is totally disengaged from the trip lever. The cam 42 is on a shaft 47 geared to the shaft 18 carrying the planet carrier 17. If the meter is not provided with means for collecting a fixed charge, the cam 42 comprises a circular disc with a slot 54, Fig. 5, wide enough to receive the roller 41. A modified form of cam 42 is shown in Fig. 6 and comprises a cylinder having two grooves 55, 56 constituting the dwells and joined by a helical groove 57 forming the actuating surface and corresponding to the portion 46. The arm 40 is provided with a pin 58 to engage in the grooves 55, 56, 57. The coin holder mechanism may be as described in Specification 424,439 and the switch and switch tripping mechanism as described in Specifications 253,242 and 274,559, [both in Class 38 (v)]. Indicators.-Two pointers 32, 33 driven from the shaft 18 move over dials graduated respectively in pence and shillings in each direction to indicate credit and arrears. To indicate whether the dials show a credit or debit, a further pointer 34 is geared to the shillings pointer so as to make less than half a revolution in either direction and moves over a dial 35 showing amounts prepaid' and ' amounts owing.'